S.W.O.R.D. is a division of S.H.I.E.L.D. that was only mentioned in a deleted scene.
In an alternate ending, Erik Selvig and Jane Foster along with S.H.I.E.L.D. employees Jasper Sitwell and other agents attempt to create a portal so that Thor can find his way back to Earth. It is mentioned that they are working off of the "Foster Theory" and that they will running simulations on wormholes with the S.H.I.E.L.D. astrophysical records and the S.W.O.R.D. database.